Dry-day rate calendar for May
Period: observations for 1996–2025 (30 years)
This month is known for some of the most stable weather in the annual cycle, and in the 1996–2025 records the dry-day rate is also on the high side at many stations. The same records show rainy days increasing in Okinawa and Amami from around the end of the month.
The "dry-day rate" is the share of years in which a given day had no precipitation (rain or snow) of 1 mm or more (daily rainfall under 1 mm, smoothed over the 4 days before and after).
These are statistics compiled from observations for 1996–2025 (30 years), not a weather forecast for any particular day. For the latest forecasts, see the JMA website.
May at a glance
The station with the highest monthly average dry-day rate in Japan, the national median, and the station with the lowest. The most comfortable stations this month: Fukushima / Kofu / Ueda (details in the comfort section below).
Dry-day rates across Japan (May average)
Each dot is 1 station. The highest and lowest stations are labeled on the map, and the top and bottom lists are below.
Daily calendar for major stations
The deeper the amber, the more years that day stayed dry (the colors match the legend above). The table below (averages for the early, middle, and late parts of the month) has the same values.
| Station | Early | Mid | Late | Monthly avg. | 2 days in a row | 3 days in a row | Windy days | Sunshine (avg.) |
|---|---|---|---|---|---|---|---|---|
| Sapporo | 68.8% | 72.7% | 75.6% | 72.4% | 55.9% | 42.0% | 22.0% | 6.5 hours |
| Sendai | 76.7% | 69.4% | 70.7% | 72.2% | 55.1% | 41.5% | 6.7% | 6.3 hours |
| Niigata | 66.6% | 65.9% | 69.3% | 67.3% | 48.5% | 33.8% | 7.5% | 6.6 hours |
| Kanazawa | 65.4% | 65.3% | 70.8% | 67.3% | 49.9% | 36.8% | 14.0% | 6.8 hours |
| Tokyo | 67.8% | 65.9% | 66.9% | 66.9% | 48.4% | 33.6% | 5.9% | 5.8 hours |
| Nagoya | 67.8% | 66.8% | 70.8% | 68.5% | 51.5% | 37.5% | 7.2% | 6.6 hours |
| Osaka | 70.4% | 66.5% | 71.7% | 69.6% | 53.4% | 40.1% | 1.3% | 6.7 hours |
| Hiroshima | 69.8% | 72.1% | 74.2% | 72.1% | 55.8% | 42.4% | 5.3% | 6.9 hours |
| Takamatsu | 72.5% | 71.6% | 76.7% | 73.7% | 57.3% | 43.8% | 2.7% | 6.8 hours |
| Fukuoka | 70.2% | 72.1% | 74.6% | 72.4% | 57.2% | 44.7% | 3.1% | 6.7 hours |
| Kagoshima | 66.4% | 68.7% | 68.5% | 67.9% | 50.2% | 36.2% | 4.6% | 5.7 hours |
| Naha | 68.3% | 60.4% | 53.5% | 60.5% | 41.6% | 28.1% | 42.5% | 4.3 hours |
"2 days in a row" and "3 days in a row" are the monthly averages of the share of years in which it stayed dry for 2 / 3 days starting that day (counted from the actual consecutive records, not by multiplying each day's share). They are a guide for multi-night trips and outdoor plans. "Windy days" is the share of days with a daily mean wind speed of 5 m/s or more. The sunshine averages include estimates from March 2021 onward at some stations.
Stations with the highest and lowest dry-day rates (May average)
Highest
Cape Saigo / Waniura / Saigo / Mitsushima / Fukushima / Ama / Matsumoto / Kofu / Kukokitamachi / Takamatsu
Lowest
Naze / Oku / Yakushima Island / Hachijojima Island / Kamiichi / Itokazu / Tokashiki / Hachimantai / Sasunabe / Yaemigahara
Comfort in May (5 levels)
Based on observations of dry-day rate, sunshine, wind, and temperature for 1996–2025 (30 years), each station is rated on 5 levels of comfort for May. The tables also show the values behind each rating and the factor that lowered it most (the main factor). Some stations with short sunshine records are not rated.
Each dot is 1 station. The colors match the levels in the legend. The top and bottom lists are below.
Most comfortable stations (top)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Fukushima | Comfortable | None | 74.9% | 6.3 hours | 1.9% | 23.4°C | 12.2°C |
| Kofu | Comfortable | None | 74.3% | 6.6 hours | 1.1% | 25.5°C | 13.9°C |
| Ueda | Comfortable | None | 73.2% | 6.9 hours | 0.0% | 23.6°C | 10.4°C |
| Imabari | Comfortable | None | 73.3% | 6.7 hours | 0.2% | 23.5°C | 13.9°C |
| Yamagata | Comfortable | None | 73.0% | 6.4 hours | 0.1% | 22.8°C | 10.8°C |
| Kasaoka | Comfortable | None | 72.7% | 6.5 hours | 0.2% | 23.8°C | 13.8°C |
| Fukuyama | Comfortable | None | 72.6% | 6.9 hours | 0.2% | 24.2°C | 13.4°C |
| Tadotsu | Comfortable | None | 72.9% | 6.9 hours | 0.7% | 24.0°C | 15.2°C |
| Kurashiki | Comfortable | None | 72.4% | 6.2 hours | 0.1% | 24.4°C | 14.3°C |
| Ikuchijima Island | Comfortable | None | 72.6% | 6.2 hours | 0.5% | 22.8°C | 13.7°C |
Harshest stations (bottom)
| Station | Level | Main factor | Dry-day rate | Sunshine (avg.) | Windy days | High (avg.) | Low (avg.) |
|---|---|---|---|---|---|---|---|
| Yonagunijima Island | Tough | Heat | 61.7% | 4.5 hours | 54.6% | 28.1°C | 23.5°C |
| Ishigakijima Island | Tough | Heat | 67.6% | 5.2 hours | 29.4% | 28.8°C | 24.1°C |
| Ohara | Fair | Heat | 63.3% | 4.3 hours | 14.8% | 28.5°C | 23.1°C |
| Ibaruma | Fair | Heat | 63.5% | 4.1 hours | 9.4% | 28.0°C | 23.5°C |
| Hateruma | Fair | Heat | 68.0% | 4.9 hours | 22.8% | 28.6°C | 23.7°C |
| Miyakojima Island | Fair | Heat | 63.9% | 4.7 hours | 24.0% | 27.8°C | 23.2°C |
| Naha | Fair | Heat | 60.5% | 4.3 hours | 42.5% | 27.1°C | 22.2°C |
| Cape Soya | Fair | Cold | 73.1% | 5.4 hours | 77.8% | 11.7°C | 5.3°C |
| Iriomotejima Island | Fair | Heat | 65.8% | 4.9 hours | 13.0% | 28.4°C | 23.0°C |
| Hamaoni-Shibetsu | Fair | Cold | 69.9% | 5.3 hours | 45.0% | 12.1°C | 4.5°C |
Stations are ordered by their rating from the observations. "Windy days" is the share of days with a daily mean wind speed of 5 m/s or more, and "Sunshine (avg.)" is the monthly average of daily sunshine hours (including estimates from March 2021 onward at some stations).
Typhoon approaches in May (5 broad areas)
| Area | Total approach days (1951–2025) |
|---|---|
| Hokkaido | 0 days |
| Honshu | 6 days |
| Shikoku | 4 days |
| Kyushu | 7 days |
| Okinawa and Amami | 45 days |
The total number of days in May on which the center of a typhoon came within 300 km of a staffed weather station in each area, from 75 years of confirmed records. The bars compare the areas within this table, with the busiest area drawn longest. The Izu and Ogasawara Islands are not included in Honshu (listed separately).
Typhoon approach calendar / Look up past typhoons by date range
What makes May distinctive
May is when the places prone to rain shift to the south. In measurements over 30 years (1996–2025), the low side was lined with Naze (52.5%) / Yakushima Island (57.7%) / Nago (59.4%), and Naha also stayed at 60.5%. In the Nansei Islands and Amami, the rainy season begins earlier than on Honshu, and the high and low sides trade places compared with winter. Taking the high side instead were inland stations, Saigo (75.7%) / Fukushima (74.9%) / Matsumoto (74.3%), along with Takamatsu (73.7%) on the Seto Inland Sea. The nationwide average was 67.8%, and the 3-day figure, at 36.6%, also falls on the solid side for the year.
In temperature terms, too, conditions for getting around lined up over a wide area. Average highs at major stations on Honshu entered the 20s, with Osaka at 25.1°C / Takamatsu at 25°C / Nagoya at 24.9°C, stepping down to the north with Sapporo at 18.2°C and Nemuro at 12.2°C. The bottom of the average lows was Etanbetsu at 3.8°C / Omu at 4.2°C, and below-freezing mornings disappeared from the table. For outdoor plans over several nights, the Seto Inland Sea side, with a high share of 3 straight days without precipitation such as Fukuoka (44.7%) / Takamatsu (43.8%), makes a good base. Days with a daily mean wind speed of 5 m/s or more were at Cape Muroto (68.7%) / Yonagunijima Island (54.6%), a calmer level than in winter.
The record values in this commentary are as compiled in September 2026, and the normals are based on 1996–2025 (30 years).
Other months and calendars
Cherry blossom calendar (some stations have recorded flowering or full bloom in May)
When to travel calendar (holidays, long weekends, and comfort levels for 12 months at once)
Each station's page also has a 12-month calendar for that station.